I don't know about that specific "school", but if you want to become a professional gunsmith, no mail order or internet school is going to do much for you.
These schools are such that no instructor ever sees your work, so you have no real idea if what you're doing is right.
What they're selling is a package of instruction that may have been written by a genuine pro, or some guy in his basement who is an incompetent.
Again, you have no way of knowing.
If you just want to work on your own guns, these courses are better than nothing.
However, if you intend to work on other peoples guns, and take money for doing it, you need to attend a real gunsmithing school like the Colorado School of Trades, or Trinidad Junior College. There are others, and these schools are known for turning out stone cold pros that can get hired anywhere.
The mail order schools are known for taking your money.